Proximal femoral focal deficiency: radiologic analysis of 49 cases

Proximal femoral focal deficiency, an uncommon congenital anomaly, necessitates early radiologic classification for surgical planning and treatment. Objective radiographic criteria, including femoral length index, acetabular depth index, acetabular angle index, and shape of the proximal femur were determined in 49 patients before cartilaginous ossification of the femoral capital epiphysis; final classification was based on follow-up radiographs or findings at arthrography or surgery. These parameters were analyzed to determine the accuracy and contributions of each in classification. Correct classification into one of three groups was possible in 86% of cases with use of three of the parameters: femoral length index, acetabular depth index, and shape of the proximal femur. The acetabular angle was found to contribute insignificantly to classification. Magnetic resonance imaging, used in only one case, depicted the nonossified cartilaginous femoral capital epiphysis, thus obviating the need for invasive diagnostic procedures and facilitating early classification.     

Evaluation of three disk tests for identification of enterococci, leuconostocs, and pediococci.

Simple rapid tests for presumptive identification of catalase-negative non-beta-hemolytic cocci (i.e., enterococci, leuconostocs, and pediococci) have not previously been available. Seven hundred thirty-four strains of aerobic and facultatively anaerobic, catalase-negative, non-beta-hemolytic gram-positive cocci were tested for susceptibility to vancomycin (Vans) by a screening procedure and production of leucine aminopeptidase (LAPase) and pyrrolidonylarylamidase (PYRase) in disk tests. Three unique patterns of activity in response to the three disks (30 micrograms of vancomycin, PYRase, and LAPase) can be used to presumptively identify the vancomycin-resistant (Vanr) enterococci (Vanr and PYRase and LAPase positive), leuconostocs (Vanr and PYRase and LAPase negative), and pediococci (Vanr, PYRase negative, and LAPase positive). The results indicate that, together with Gram stain characteristics and the catalase test, the vancomycin, LAPase, and PYRase disk tests can be used to presumptively identify Vanr strains of enterococci as well as Leuconostoc and Pediococcus strains from human infections.     

M protein gene type distribution among group A streptococcal clinical isolates recovered in Mexico City,Mexico, from 1991 to 2000, and Durango,Mexico, from 1998 to 1999: overlap with type distribution within the United States

To examine the type distribution of pathogenic group A streptococcal (GAS) strains in Mexico, we determined the emm types of 423 GAS isolates collected from ill patients residing in Mexico (Durango or Mexico City). These included 282 throat isolates and 107 isolates from normally sterile sites. Of the other isolates, 38 were recovered from other miscellaneous infections. A total of 31 different emm types were found, revealing a broad overlap between commonly occurring emm types in Mexico and the United States. The information obtained in this study is consistent with the possibility that multivalent, M type-specific vaccines prepared for GAS strain distribution within the United States could theoretically protect against the majority of GAS strains causing disease in the two cities surveyed in Mexico.     

Six-month multicenter study on invasive infections due to Streptococcus pyogenes and Streptococcus dysgalactiae subsp. equisimilis in Argentina

During a 6-month period, 95 invasive infections due to Streptococcus pyogenes and group C or group G Streptococcus dysgalactiae subsp. equisimilis were recorded from 40 centers of 16 cities in Argentina. We describe here epidemiologic data available for 55 and 19 patients, respectively, associated with invasive infections due to S. pyogenes and S. dysgalactiae subsp. equisimilis. The associated isolates and 58 additional pharyngeal isolates were genotyped and subjected to serologic and/or antibiotic susceptibility testing. Group A streptococcal emm type distribution and strain association with toxic shock appeared to differ somewhat from results found within the United States; however, serologic characterization and sof sequence typing suggested that emm types found in both countries are reflective of shared clonal types.     

Enzyme-linked immunosorbent assay for streptococcal M protein antibodies.

The enzyme-linked immunosorbent assay (ELISA) described by Engvall and Perlmann, which uses antigen-coated tubes and enzyme-labeled anti-immunoglobulin, has been used for the detection of antibodies against streptococcal M protein. The antigen used in the assay was obtained by guanidine extraction of type M-12 streptococcal cell walls followed by hydroxyapatite chromatography. This antigen has the capacity to elicit bactericidal antibodies in rabbits. The results show that the ELISA is specific and highly sensitive for the detection of antibodies in rabbit and human antisera. Preliminary results suggest that, when M-12 antigen is used, the antibodies detected by ELISA are the same antibodies detected in the bactericidal test. The assay has been performed with human and rabbit sera. There was a 96% agreement between bactericidal and ELISA results with rabbit sera and 97.5% agreement with human sera. All bactericidal antibody-positive sera tested thus far yielded positive ELISA results.     

Evaluation of the Directigen Group A Strep test kit

The Directigen Group A Strep test kit (Hynson, Wescott, and Dunning, Baltimore, Md.) was tested for its ability to detect group A streptococci directly from 147 throat swabs. The results were compared with results from conventional culture and Lancefield serological grouping tests. The data showed that 121 of 124 culture-negative throat specimens were also Directigen negative (98%) and that 21 of 23 culture-positive specimens were Directigen positive (91%). If specimens that provided less than 10 colonies per plate of beta-hemolytic streptococci were eliminated, all of the culture-positive specimens were Directigen positive. Positive or negative results were available within 65 to 70 min of testing. The Directigen method is relatively simple to perform and easy to interpret and provides accurate assessment of the presence or absence of group A streptococci in throat swabs, with little or no cross-reactivity with other beta-hemolytic groups.     

Major subtypes of invasive Haemophilus influenzae from 1983 to 1985 in Atlanta, Ga.

We compared outer membrane protein (OMP) patterns of Haemophilus influenzae isolated in metropolitan Atlanta, Ga., from July 1983 to June 1985. Of 74 randomly selected H. influenzae serotype b, biotype I, isolates (24% of the total number of H. influenzae, and 32% of the total number of H. influenzae serotype b, biotype I, isolates), 66 (89.2%) had the same OMP pattern. Of the remaining eight, five (6.7%) had an identical OMP pattern. The other three isolates had separate and distinct patterns. A greater diversity of OMP patterns was found with H. influenzae serotype b, biotype II, and nonserotypeable H. influenzae. Of the 18 H. influenzae serotype b, biotype II, isolates (5.8% of the total number of H. influenzae isolates), 1 had an OMP pattern similar to that of the predominate biotype I OMP type, 6 (33% of the biotype II) had the same pattern, and 11 had heterogeneous patterns. Of the 19 recoverable, nonserotypeable biotype II isolates (6.8% of the total number of H. influenzae), 18 had different OMP patterns, and no pattern was similar to those observed with serotype b. These findings indicate that most H. influenzae strains isolated during this 2-year period were indistinguishable by serotype, biotype, or OMP patterns.